Tutorial Password Protect Folder(s)
Put in .htaccess file in the directory you are trying to protect:
AuthType Basic
AuthName "This Area is Password Protected"
AuthUserFile /full/path/to/.htpasswd
Require valid-user
Ideally, the .htpasswd file will be not in a public facing directory. Put this in there:
chriscoyier:$apr1$O/BJv...$vIHV9Q7ySPkw6Mv6Kd/ZE/
That is just a sample, you can create the code for your unique username and password here.
Note that all subdirectories of this directory will also be password protected by this same system.